Typically, tissue repair to the shoulder area, such as reattaching torn rotator cuff tendons to bone, is done through open surgery. However, open surgery introduces potential problems with the trauma associated with the large area of skin, muscle and tissue which must be incised to perform such surgery.
Arthroscopic surgery has the advantages of making a small incision and therefore reducing the risk of infection, blood loss and the like which is sometimes the result of open surgery. However, arthroscopic repair of the rotator cuff through bone tunnels has not been performed, a result of, among other things, lacking the necessary instruments. For example, in attaching the rotator cuff to the humerus by suturing the tendon to the bone by passing the suture through a hole drilled through the proximal portion of the humerus, specific problems arise. Just distal to the bone tunnel site lies the axillary nerve, a major nerve which innervates the deltoid muscle. If the axillary nerve is damaged, movement of the shoulder may be impaired. Proximal to the humerus is the acromion. Thus, the location at which the tunnel is to be drilled is effectively "boxed in". This prevents the use of straight pins to bore the hole.
Applicant has provided an instrument which allows drilling a straight hole through bone in an area bordered by obstacles. Applicant has provided a device in which straight holes can be drilled in bones through the use of a flexible pin, such as a Nitinol pin, used in conjunction with a curved, tubular aiming device, and a curved tubular receiving device. Moreover, since the acromion may be different lengths in different individuals, there is needed some adjustability to the drilling device. Orthopedic drill guide devices are known in the art. For example U.S. Pat. No. 4,945,904 (Bolton, et al 1990) discloses an orthopedic drill guide device used to locate and guide the drilling of holes in bones for the purpose of implanting tissue repair devices. Specifically, the Bolton drill guide device is designed to locate, align and guide the drilling of a tibial through-hole and then to locate, align and guide the drilling of the femoral through-hole with respect the previous drilled tibial through hole. The Bolton device would be incapable of use arthroscopically for shoulder work such as reattaching torn rotator cuffs. The Bolton device, like other prior art devices, provides a device wherein the longitudinal axis of the drill guide aiming device is designed to align with the longitudinal axis of the hole which is intended to be drilled. Applicant, on the other hand, cannot use such a device because of the proximity of the axillary nerve and the acromion to the drill site.
Another prior art device for use as a drill guide is disclosed in U.S. Pat. No. 5,112,337 (Paulos, et al 1992). The Paulos patent discloses another straight tubular drill guide aiming device for alignment with the longitudinal axis of the tunnel to be drilled. Specifically, the Paulos drill guide is designed for drilling a tunnel in the tibia for anterior cruciate ligament reconstruction. The drill guide aiming device is used in conjunction with a target hook having a point for engaging and determining the exit point of the tunnel. The shortcomings of this device with respect to arthroscopic shoulder surgery are the same as Bolton, both require the use of a straight tubular aiming device with longitudinal axis coincident with the longitudinal axis of the tunnel to be drilled.
Thus, applicant's device provides for the use of a curved aiming device, tubular for receipt of a flexible pin, for alignment adjacent an entry point and drilling a straight tunnel through proximal end of the humerus, while avoiding exposure of the axillary nerve to the instrument. Applicant also provides for a curved tubular receiving device which avoids interference between the pin and the acromion. Thus, applicant provides an orthopedic drill guide device for use in drilling a straight tunnel through bone where obstructions prevent the use of straight drill aiming and receiving devices.